1. Field of the Invention
The invention concerns a fluidic system with a measuring apparatus the fluid whereof is under high pressures of several hundred bar or under reduced and/or varying pressures, said apparatus being equipped with measuring, control and/or regulating lines, each connected with measuring, control and/or regulating points of system and combined in a collector device.
2. Description of The Related Technology
For the detection of operating pressures of fluidic media, for example measuring couplings for fluidic systems are known, consisting of a coupling which in the installed state is under line pressure and in the bore whereof a spring loaded and mechanically actuable check valve is located.
This type of measuring couplings serve for example to establish testing or measuring connections on pressure lines, wherein as a rule the coupling bushing is fixedly installed in the pressure line of a fluidic system. For the duration of the testing or measuring operation, a sealing nipple in the form of a hollow plug is screwed on by means of a union nut, said nipple being fixedly connected with a hose. The couplings may be connected for example under pressure, i.e. without shutting down the installation, by means of measuring hose with the corresponding measuring instruments. In case of the connection of fixedly installed instruments, for example manometers, selective manometer switches, electric pressure transducers and pressure switches, the flexible measuring lines may be installed in the manner of electric cables, so that the expensive installation of pipes may be avoided. By means of such measuring couplings therefore effective operating pressures may be measured directly in the fluid lines, without the need for the loosening of vent screws and screwed pipe fittings. Couplings of this type are used with a great variety of structural elements and controls of fluidic systems. Following the separation of the coupling connection, the coupling bushing a protective cap is screwed onto the external threads of the bushing in order to prevent the penetration of dirt into the coupling bushing and to perform an additional sealing function in case a check valve installed in the coupling bushing is not absolutely tight.
Valve couplings of this type are known for example from DE No. 2 756 084, in which the valve bodies are in the form of cones or balls. In this known valve coupling the valve body is arranged in the form of a check valve on a compression spring and is displaceable by the latter, while comprising a flow channel on an upper contact end. The valve coupling is equipped with a sealing and antirotation ring, the sealing function of which is, however, assured only if a corresponding hose or closure cap is screwed tightly onto the coupling bushing with its sealing nipple.
If this cap is loosened or if it is not present at all--as for example in the case of selective manometer switches--the pressure medium is sealed in only by the corresponding check valve. However, due to its layout, any check valve for use in high pressure valve couplings of the aforementioned type will leak to a lesser or greater extent depending on the viscosity of the pressure medium, or cannot be manufactured in mass production so a to be tight in actual use.
For hose installation intended for use in general hydraulics and for gas feeder devices of hydraulic reservoirs such designs are adequate, but complaints concerning leakages already appear for example if caps of several valve couplings are loosened simultaneously in order to test with one measuring device several measuring locations in succession, if gas pressure testing devices are used on hydraulic reservoirs without gas refill possibilities, or if the valve couplings are used to monitor installations with combustible gases, etc.
The devices cannot be used at all with selective manometer switches in view of the constant leakage of the connections not actually in use. Attempts have already been made to in the case of the aforementioned valve couplings to equipped the check valve with rubber elastic gaskets or conventional O rings, but in spite of the initially adequate tightness, positive results were not achieved in all cases. With long measuring lines and high dead volumes in the manometers or the circulations connected and in particular with low viscosity liquids or high operating pressures, or in the case of test devices for hydraulic reservoirs, rubber elastic gaskets are washed out, as the high pressure difference upon the raising of the valve generates a very strong flow of the medium used at the seal.
For these reasons a valve couplings, preferably a measuring valve coupling, suitable for fluidic systems with high operating pressures and media with different viscosities, has already been proposed. Measures were provided to protect the seal, which consists of an elastomeric material against cavitation and washouts and to eliminate the effect of large volumes in the measuring line or the like, or the circulation connected on the elastomeric seal, by causing in a valve coupling a cylindrical valve body to press with the outer edge and/or frontal surface of its sealing shoulder in the closed state of the valve against a gasket consisting of an elastomeric material, and forming with a coupling bushing or a sealing bush located in the coupling bush a sealable flow channel, while further seals are provided downstream and/or upstream from said gasket, which upon the opening of the valve body terminate their sealing function only following the lifting of the gasket from the sealing shoulder, preferably in a delayed manner. This measure assures that the flow generated by the high pressure difference is throttled immediately after the release of the elastomeric gasket from its valve shoulder or is nearly arrested.
The decrease of the sealing function of the seals located downstream and/or upstream from the gasket during the forcing open of the valve body takes compared to the decrease in the sealing function of the gasket, over a longer stroke path. In this manner the seals located downstream and/or upstream from the gasket are still applying their sealing function, while due to its shorter stroke path, the gasket avoids the flow that otherwise would be generated, together with the cavitation or washout to which it would be exposed.
The use of hydraulic installations in combination with other system components and electrohydraulic elements requires in case of a failure or malfunction a rapid and accurate diagnosis, so that the state of certain groups of structural elements may be determined immediately. This requires the availability of the measured pressure date of as many components of the system as possible within a short period of time, preferably simultaneously. The aforedescribed measuring couplings are especially suitable for the purpose. They are installed at strategically important measuring locations of an installation and are optionally combined on an orifice plate by means of measuring lines. To actually perform the measurements, the high pressure lines must be connected individually with single measuring points. Confusion of the connections often occur during the connection process so that false measurements are carried out. Furthermore, the measuring devices connected may be damaged or destroyed, is the measured values being detected are not within the measuring range of the device.
Multiple couplings are also known, but these may be actuated manually only in case of low system pressures. In systems with high pressures, the coupling process may be carried out mechanically only, or else the system must be depressurized prior to the coupling operation.